How can I install & run testdisk with USB?
When I boot from HDD, i can download & install testdisk from ubuntu software center; but when I boot from USB (for the purpose of recovering my NTFS drives that were accidentally dissolved into one EXT4 by 14.04) I can not even find testdisk inside ubuntu software center. So can not run testdisk from terminal when I boot from USB.
Is booting from USB a MUST for trying to recover NTFS drives?
Please help I am badly confused :( :`(
As muru has mentioned, you need to enable the universe repos to install testdisk in Ubuntu. However, I would recommend using one of the Live Rescue CDs listed here instead, rather than an Ubuntu cd/usb. They're basically Linux distros that come with a ton of data recovery/repair programs installed, including testdisk.
The advantage of this is that you have a ton of programs dedicated to data recovery all in one place, but more importantly, many of them are configured to never touch the HDD during boot. When you're doing data recovery, the more you access/modify the data on the drive, the less likely you'll be able to recover data. Ubuntu accesses the hard disk quite a bit during boot, even when using a live cd/usb, which makes it not quite ideal for data recovery purposes.
testdiskis in theuniversesection of the repositories. Just enable it in Software Sources. See askubuntu.com/a/148645/158442